/*
** $Id: ldebug.c,v 2.90 2012/08/16 17:34:28 roberto Exp $
** Debug Interface
** See Copyright Notice in lua.h
*/


#include <stdarg.h>
#include <stddef.h>
#include <string.h>


#define ldebug_c
#define LUA_CORE

#include "lua.h"

#include "lapi.h"
#include "lcode.h"
#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lvm.h"



#define noLuaClosure(f)		((f) == NULL || (f)->c.tt == LUA_TCCL)


static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);


static int currentpc (CallInfo *ci) {
	lua_assert(isLua(ci));
	return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
}


static int currentline (CallInfo *ci) {
	return getfuncline(ci_func(ci)->p, currentpc(ci));
}


/*
** this function can be called asynchronous (e.g. during a signal)
*/
LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
	if (func == NULL || mask == 0) {  /* turn off hooks? */
		mask = 0;
		func = NULL;
	}
	if (isLua(L->ci))
		L->oldpc = L->ci->u.l.savedpc;
	L->hook = func;
	L->basehookcount = count;
	resethookcount(L);
	L->hookmask = cast_byte(mask);
	return 1;
}


LUA_API lua_Hook lua_gethook (lua_State *L) {
	return L->hook;
}


LUA_API int lua_gethookmask (lua_State *L) {
	return L->hookmask;
}


LUA_API int lua_gethookcount (lua_State *L) {
	return L->basehookcount;
}


LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
	int status;
	CallInfo *ci;
	if (level < 0) return 0;  /* invalid (negative) level */
	lua_lock(L);
	for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
		level--;
	if (level == 0 && ci != &L->base_ci) {  /* level found? */
		status = 1;
		ar->i_ci = ci;
	}
	else status = 0;  /* no such level */
	lua_unlock(L);
	return status;
}


static const char *upvalname (Proto *p, int uv) {
	TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
	if (s == NULL) return "?";
	else return getstr(s);
}


static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
	int nparams = clLvalue(ci->func)->p->numparams;
	if (n >= ci->u.l.base - ci->func - nparams)
		return NULL;  /* no such vararg */
	else {
		*pos = ci->func + nparams + n;
		return "(*vararg)";  /* generic name for any vararg */
	}
}


static const char *findlocal (lua_State *L, CallInfo *ci, int n,
							  StkId *pos) {
								  const char *name = NULL;
								  StkId base;
								  if (isLua(ci)) {
									  if (n < 0)  /* access to vararg values? */
										  return findvararg(ci, -n, pos);
									  else {
										  base = ci->u.l.base;
										  name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
									  }
								  }
								  else
									  base = ci->func + 1;
								  if (name == NULL) {  /* no 'standard' name? */
									  StkId limit = (ci == L->ci) ? L->top : ci->next->func;
									  if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
										  name = "(*temporary)";  /* generic name for any valid slot */
									  else
										  return NULL;  /* no name */
								  }
								  *pos = base + (n - 1);
								  return name;
}


LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
	const char *name;
	lua_lock(L);
	if (ar == NULL) {  /* information about non-active function? */
		if (!isLfunction(L->top - 1))  /* not a Lua function? */
			name = NULL;
		else  /* consider live variables at function start (parameters) */
			name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
	}
	else {  /* active function; get information through 'ar' */
		StkId pos = 0;  /* to avoid warnings */
		name = findlocal(L, ar->i_ci, n, &pos);
		if (name) {
			setobj2s(L, L->top, pos);
			api_incr_top(L);
		}
	}
	lua_unlock(L);
	return name;
}


LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
	StkId pos = 0;  /* to avoid warnings */
	const char *name = findlocal(L, ar->i_ci, n, &pos);
	lua_lock(L);
	if (name)
		setobjs2s(L, pos, L->top - 1);
	L->top--;  /* pop value */
	lua_unlock(L);
	return name;
}


static void funcinfo (lua_Debug *ar, Closure *cl) {
	if (noLuaClosure(cl)) {
		ar->source = "=[C]";
		ar->linedefined = -1;
		ar->lastlinedefined = -1;
		ar->what = "C";
	}
	else {
		Proto *p = cl->l.p;
		ar->source = p->source ? getstr(p->source) : "=?";
		ar->linedefined = p->linedefined;
		ar->lastlinedefined = p->lastlinedefined;
		ar->what = (ar->linedefined == 0) ? "main" : "Lua";
	}
	luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
}


static void collectvalidlines (lua_State *L, Closure *f) {
	if (noLuaClosure(f)) {
		setnilvalue(L->top);
		api_incr_top(L);
	}
	else {
		int i;
		TValue v;
		int *lineinfo = f->l.p->lineinfo;
		Table *t = luaH_new(L);  /* new table to store active lines */
		sethvalue(L, L->top, t);  /* push it on stack */
		api_incr_top(L);
		setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
		for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
			luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
	}
}


static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
					   Closure *f, CallInfo *ci) {
						   int status = 1;
						   for (; *what; what++) {
							   switch (*what) {
							   case 'S': {
								   funcinfo(ar, f);
								   break;
										 }
							   case 'l': {
								   ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
								   break;
										 }
							   case 'u': {
								   ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
								   if (noLuaClosure(f)) {
									   ar->isvararg = 1;
									   ar->nparams = 0;
								   }
								   else {
									   ar->isvararg = f->l.p->is_vararg;
									   ar->nparams = f->l.p->numparams;
								   }
								   break;
										 }
							   case 't': {
								   ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
								   break;
										 }
							   case 'n': {
								   /* calling function is a known Lua function? */
								   if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
									   ar->namewhat = getfuncname(L, ci->previous, &ar->name);
								   else
									   ar->namewhat = NULL;
								   if (ar->namewhat == NULL) {
									   ar->namewhat = "";  /* not found */
									   ar->name = NULL;
								   }
								   break;
										 }
							   case 'L':
							   case 'f':  /* handled by lua_getinfo */
								   break;
							   default: status = 0;  /* invalid option */
							   }
						   }
						   return status;
}


LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
	int status;
	Closure *cl;
	CallInfo *ci;
	StkId func;
	lua_lock(L);
	if (*what == '>') {
		ci = NULL;
		func = L->top - 1;
		api_check(L, ttisfunction(func), "function expected");
		what++;  /* skip the '>' */
		L->top--;  /* pop function */
	}
	else {
		ci = ar->i_ci;
		func = ci->func;
		lua_assert(ttisfunction(ci->func));
	}
	cl = ttisclosure(func) ? clvalue(func) : NULL;
	status = auxgetinfo(L, what, ar, cl, ci);
	if (strchr(what, 'f')) {
		setobjs2s(L, L->top, func);
		api_incr_top(L);
	}
	if (strchr(what, 'L'))
		collectvalidlines(L, cl);
	lua_unlock(L);
	return status;
}


/*
** {======================================================
** Symbolic Execution
** =======================================================
*/

static const char *getobjname (Proto *p, int lastpc, int reg,
							   const char **name);


/*
** find a "name" for the RK value 'c'
*/
static void kname (Proto *p, int pc, int c, const char **name) {
	if (ISK(c)) {  /* is 'c' a constant? */
		TValue *kvalue = &p->k[INDEXK(c)];
		if (ttisstring(kvalue)) {  /* literal constant? */
			*name = svalue(kvalue);  /* it is its own name */
			return;
		}
		/* else no reasonable name found */
	}
	else {  /* 'c' is a register */
		const char *what = getobjname(p, pc, c, name); /* search for 'c' */
		if (what && *what == 'c') {  /* found a constant name? */
			return;  /* 'name' already filled */
		}
		/* else no reasonable name found */
	}
	*name = "?";  /* no reasonable name found */
}


/*
** try to find last instruction before 'lastpc' that modified register 'reg'
*/
static int findsetreg (Proto *p, int lastpc, int reg) {
	int pc;
	int setreg = -1;  /* keep last instruction that changed 'reg' */
	for (pc = 0; pc < lastpc; pc++) {
		Instruction i = p->code[pc];
		OpCode op = GET_OPCODE(i);
		int a = GETARG_A(i);
		switch (op) {
		case OP_LOADNIL: {
			int b = GETARG_B(i);
			if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
				setreg = pc;
			break;
						 }
		case OP_TFORCALL: {
			if (reg >= a + 2) setreg = pc;  /* affect all regs above its base */
			break;
						  }
		case OP_CALL:
		case OP_TAILCALL: {
			if (reg >= a) setreg = pc;  /* affect all registers above base */
			break;
						  }
		case OP_JMP: {
			int b = GETARG_sBx(i);
			int dest = pc + 1 + b;
			/* jump is forward and do not skip `lastpc'? */
			if (pc < dest && dest <= lastpc)
				pc += b;  /* do the jump */
			break;
					 }
		case OP_TEST: {
			if (reg == a) setreg = pc;  /* jumped code can change 'a' */
			break;
					  }
		default:
			if (testAMode(op) && reg == a)  /* any instruction that set A */
				setreg = pc;
			break;
		}
	}
	return setreg;
}


static const char *getobjname (Proto *p, int lastpc, int reg,
							   const char **name) {
								   int pc;
								   *name = luaF_getlocalname(p, reg + 1, lastpc);
								   if (*name)  /* is a local? */
									   return "local";
								   /* else try symbolic execution */
								   pc = findsetreg(p, lastpc, reg);
								   if (pc != -1) {  /* could find instruction? */
									   Instruction i = p->code[pc];
									   OpCode op = GET_OPCODE(i);
									   switch (op) {
									   case OP_MOVE: {
										   int b = GETARG_B(i);  /* move from 'b' to 'a' */
										   if (b < GETARG_A(i))
											   return getobjname(p, pc, b, name);  /* get name for 'b' */
										   break;
													 }
									   case OP_GETTABUP:
									   case OP_GETTABLE: {
										   int k = GETARG_C(i);  /* key index */
										   int t = GETARG_B(i);  /* table index */
										   const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
											   ? luaF_getlocalname(p, t + 1, pc)
											   : upvalname(p, t);
										   kname(p, pc, k, name);
										   return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
														 }
									   case OP_GETUPVAL: {
										   *name = upvalname(p, GETARG_B(i));
										   return "upvalue";
														 }
									   case OP_LOADK:
									   case OP_LOADKX: {
										   int b = (op == OP_LOADK) ? GETARG_Bx(i)
											   : GETARG_Ax(p->code[pc + 1]);
										   if (ttisstring(&p->k[b])) {
											   *name = svalue(&p->k[b]);
											   return "constant";
										   }
										   break;
													   }
									   case OP_SELF: {
										   int k = GETARG_C(i);  /* key index */
										   kname(p, pc, k, name);
										   return "method";
													 }
									   default: break;  /* go through to return NULL */
									   }
								   }
								   return NULL;  /* could not find reasonable name */
}


static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
	TMS tm;
	Proto *p = ci_func(ci)->p;  /* calling function */
	int pc = currentpc(ci);  /* calling instruction index */
	Instruction i = p->code[pc];  /* calling instruction */
	switch (GET_OPCODE(i)) {
	case OP_CALL:
	case OP_TAILCALL:  /* get function name */
		return getobjname(p, pc, GETARG_A(i), name);
	case OP_TFORCALL: {  /* for iterator */
		*name = "for iterator";
		return "for iterator";
					  }
					  /* all other instructions can call only through metamethods */
	case OP_SELF:
	case OP_GETTABUP:
	case OP_GETTABLE: tm = TM_INDEX; break;
	case OP_SETTABUP:
	case OP_SETTABLE: tm = TM_NEWINDEX; break;
	case OP_EQ: tm = TM_EQ; break;
	case OP_ADD: tm = TM_ADD; break;
	case OP_SUB: tm = TM_SUB; break;
	case OP_MUL: tm = TM_MUL; break;
	case OP_DIV: tm = TM_DIV; break;
	case OP_MOD: tm = TM_MOD; break;
	case OP_POW: tm = TM_POW; break;
	case OP_UNM: tm = TM_UNM; break;
	case OP_LEN: tm = TM_LEN; break;
	case OP_LT: tm = TM_LT; break;
	case OP_LE: tm = TM_LE; break;
	case OP_CONCAT: tm = TM_CONCAT; break;
	default:
		return NULL;  /* else no useful name can be found */
	}
	*name = getstr(G(L)->tmname[tm]);
	return "metamethod";
}

/* }====================================================== */



/*
** only ANSI way to check whether a pointer points to an array
** (used only for error messages, so efficiency is not a big concern)
*/
static int isinstack (CallInfo *ci, const TValue *o) {
	StkId p;
	for (p = ci->u.l.base; p < ci->top; p++)
		if (o == p) return 1;
	return 0;
}


static const char *getupvalname (CallInfo *ci, const TValue *o,
								 const char **name) {
									 LClosure *c = ci_func(ci);
									 int i;
									 for (i = 0; i < c->nupvalues; i++) {
										 if (c->upvals[i]->v == o) {
											 *name = upvalname(c->p, i);
											 return "upvalue";
										 }
									 }
									 return NULL;
}


l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
	CallInfo *ci = L->ci;
	const char *name = NULL;
	const char *t = objtypename(o);
	const char *kind = NULL;
	if (isLua(ci)) {
		kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
		if (!kind && isinstack(ci, o))  /* no? try a register */
			kind = getobjname(ci_func(ci)->p, currentpc(ci),
			cast_int(o - ci->u.l.base), &name);
	}
	if (kind)
		luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
		op, kind, name, t);
	else
		luaG_runerror(L, "attempt to %s a %s value", op, t);
}


l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
	if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
	lua_assert(!ttisstring(p1) && !ttisnumber(p2));
	luaG_typeerror(L, p1, "concatenate");
}


l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
	TValue temp;
	if (luaV_tonumber(p1, &temp) == NULL)
		p2 = p1;  /* first operand is wrong */
	luaG_typeerror(L, p2, "perform arithmetic on");
}


l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
	const char *t1 = objtypename(p1);
	const char *t2 = objtypename(p2);
	if (t1 == t2)
		luaG_runerror(L, "attempt to compare two %s values", t1);
	else
		luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
}


static void addinfo (lua_State *L, const char *msg) {
	CallInfo *ci = L->ci;
	if (isLua(ci)) {  /* is Lua code? */
		char buff[LUA_IDSIZE];  /* add file:line information */
		int line = currentline(ci);
		TString *src = ci_func(ci)->p->source;
		if (src)
			luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
		else {  /* no source available; use "?" instead */
			buff[0] = '?'; buff[1] = '\0';
		}
		luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
	}
}


l_noret luaG_errormsg (lua_State *L) {
	if (L->errfunc != 0) {  /* is there an error handling function? */
		StkId errfunc = restorestack(L, L->errfunc);
		if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
		setobjs2s(L, L->top, L->top - 1);  /* move argument */
		setobjs2s(L, L->top - 1, errfunc);  /* push function */
		L->top++;
		luaD_call(L, L->top - 2, 1, 0);  /* call it */
	}
	luaD_throw(L, LUA_ERRRUN);
}


l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
	va_list argp;
	va_start(argp, fmt);
	addinfo(L, luaO_pushvfstring(L, fmt, argp));
	va_end(argp);
	luaG_errormsg(L);
}

